Determination of Vts from D -> K* l nu and B -> K* gamma data via heavy quark symmetry and perturbative QCD

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We use heavy quark effective theory (HQET) and perturbative QCD to study the heavy meson -- light vector meson transitions involved in D and B decays. HQET is used to relate the measured D -> K* l nu vector and axial-vector form factors at four-momentum transfer q² = 0 to the B -> K* gamma tensor and axial-tensor form factors at q² = 16.5 GeV². Perturbative QCD is then used to find matching conditions for the B-meson form factors at q² = 0. A five parameter ``vector dominance'' type fit of the two HQET form factors, consisting of single pole, double pole, and subtraction terms, is used to match the data at q² = 16.5 GeV² to QCD at q² = 0. The values at q² = 0 are compared with recent data on the exclusive rate for B -> K* gamma decay to extract a value for the Cabibbo-Kobayashi-Maskawa matrix element Vts = 0.035, with 28% experimental uncertainty, and 32% theoretical uncertainty from higher order QCD effects and violations of heavy quark symmetry.